1. Field of the Invention
The present invention relates to a semiconductor integrated circuit and, more particularly, to a technique for reducing the power consumption of a semiconductor integrated circuit.
2. Description of the Related Art
Recently, mobile electronic devices (e.g., a mobile telephone) driven by a battery have been commonly used. There have been a strong demand for a semiconductor integrated circuit to be mounted on those mobile electronic devices to have a high-speed operation in order to achieve the advanced functions of the electronic devices and to have a low power consumption for enabling the battery to run for a long time.
In the semiconductor integrated circuit constituted of a plurality of circuit blocks, the wiring lengths of inter-block signal lines (e.g., global signal lines) for transmitting signals between the circuit blocks have been increasing, causing one of major factors to deteriorate the performances (e.g., the operation speed or the power consumption) of the semiconductor integrated circuit. In view of solving the problem, there have been developed the techniques for improving the performances of the semiconductor integrated circuit having the signal lines of long wiring lengths. For example, Japanese Unexamined Patent Application Publication No. 9-294063 discloses a technique for relaxing the voltage fluctuations of a power supply line by speeding up the signal transmissions through signal lines of long wiring lengths.
Further, Japanese Unexamined Patent Application Publication No. 9-190693 discloses a technique for preventing a feedthrough current from flowing in a circuit to be connected with a data line even in a case where the potential of the data line is to be equalized in advance to an intermediate potential in the semiconductor memory device.
In recent years, the power consumption due to a signal line of a long wiring length (e.g., a signal line of a large load) such as an inter-block signal line has largely accounted for the total power consumption of the semiconductor integrated circuit. For realizing the low power consumption of the semiconductor integrated circuit, therefore, it is essential to reduce the power consumption due to the signal line of a large load.